Had a great time seeing everyone again at SESF! It wouldn't be a road trip if I didn't have a new electrical gremlin to sort out as a souvenir...
Car is a 1984 Euro 635CSi.
Coming home at night Sunday I got a Check Control error for Tail Light not working. This error started for the first time the day before I left for SESF but seemed to be intermittent as it didn't happen the next couple times I drove at night.
Started troubleshooting today. Replaced right tail light bulb with new one (Silvania 5007) and noticed no change. Swapped side to side bulbs and right side bulb still did not illuminate. Upon inspection I noticed several other lights are now not working.
Lights that are NOT working currently:
1. Right tail light bulb
2. Hood light (when light switch is on)
3. Right "city light" within E-code headlights
4. Right front corner parking light
5. Right rear corner light
6. Glove box light
Lights that ARE working currently:
1. Headlights - BOTH sides
2. Brights - BOTH sides
3. Fog lights - BOTH sides
4. Brake lights - BOTH sides
5. Passenger visor mirror light (with light switch on)
6. Left "city light" within E-code headlights
7. Interior Dome Lights/OBC/Cluster/Radio, etc.
8. Turn signals/Emergency flashers - ALL 4 Corners
I pulled every fuse today and verified none were blown - also matched up to fuse box diagram for correct amperage. I disconnected and cleaned the Check Control wiring connection and reinstalled. I cleaned the ground near the battery as well as the one on the firewall.
All of the lights that are not working currently were working fine a week ago so this issue must be related. I took a quick look at the Wiring Diagrams but didn't see a link between all of my non-working lights (they seemed to be spread across multiple grounds).
Would love some ideas before I dig any deeper if anyone has had a similar issue?
Abbey had a similar issue and recently did a video on isolating and troubleshooting electrical gremlins.
Well-worth watching:
https://www.youtube.com/watch?v=HBsw...elLXZW&index=5
Her other E24 project videos in the playlist are also great.
Last edited by TimU; 04-27-2022 at 05:04 AM.
Bump - wasn't the main relay and I'm still working my way through checking grounds. Still open to ideas if anyone else has had a similar issue.
I was suspecting you have some trouble in the headlight switch, so I was checking out the '86 E24 ETM. I've had a few of them fail, usually the dimmer pot is the first part to go. I believe they can be opened up and refurbished, but it's been a while since I was in there. The early E30 might have a compatible switch; they do look quite similar overall. I think the headlight connector is easily accessible from the dash kick panel, and it might be possible to test by shorting out the pins in the connector instead of pulling it all apart. The switch clips into the back of the dash bezel, I think. It can't be removed unless you unscrew the headlight control knob.
The affected parking lights are all on Fuse 23. That circuit is powered with a gray/green wire to pin 10 on the headlight switch. In either 'park' or 'headlight' selection, it powers up pin 1, out through a grey/white to all the right side parking lights and the hood light.
The odd one is the glove box light. It should always be hot, powered via Fuse 21 through connector C205, grounded by the glove box switch to a dash ground.
I have seen some fuse boxes with heat damage over the years. The plastic melts a bit and allows the fuse to loose up. It's a lot of work to take one of those apart, but they're pretty simple. I think they're shared with the E30, among other 80s BMWs.
Save the manuals!
'08 128i 6MT, '86 635CSi 5MT (B32, Motronic 1.3, WBO2, G265, 18# FW, 3.46 torsen)
Past projects:
'96 318iS, sold 4/23 '90 535iM, RIP 1/23 '90 535iA RIP 6/22 '91 318i, sold 7/19 '97 M3 sedan, sold 11/18 '85 735i, RIP 2/18 '92 325iC, sold 7/16 '91 318iS, sold 6/16 '84 745i, sold 10/14 '82 633CSi, traded 9/12 '90 325i, RIP '87 325 sold '89 525i, traded '87 325iS, RIP
Thanks for the tip on the Headlight switch - I will dig in and report back.
DesktopDave you are amazing! It was a loose connection at the rear of the headlight switch where it connects to the cluster. Instantly restored all exterior Right Hand side lighting as well as hood and trunk. The only one still non-functional is the glove box light, and like you said that's on a different circuit. Perhaps that one genuinely just is needing a bulb. It was working about a month ago.
I probably would have spent hours chasing additional grounds if it wasn't for your tip - Thank you!
That's good to hear, thanks for the update. Always nice to nail down those little gremlins.
I've had many of those glove box lights destroyed by corroded battery cells internally. I hope it's just the bulb!
Save the manuals!
'08 128i 6MT, '86 635CSi 5MT (B32, Motronic 1.3, WBO2, G265, 18# FW, 3.46 torsen)
Past projects:
'96 318iS, sold 4/23 '90 535iM, RIP 1/23 '90 535iA RIP 6/22 '91 318i, sold 7/19 '97 M3 sedan, sold 11/18 '85 735i, RIP 2/18 '92 325iC, sold 7/16 '91 318iS, sold 6/16 '84 745i, sold 10/14 '82 633CSi, traded 9/12 '90 325i, RIP '87 325 sold '89 525i, traded '87 325iS, RIP
Glove box light fixed as well - strangely the connection was unplugged. Maybe something bumped it when I was putting things back in the glove box recently - kinda a weird one.
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